And he says the players have returned in far better condition than they did a year ago.
Speaking at the club's first pre-season training session on Monday at Visy Park, Ratten said the former Fremantle ruckman, acquired in the exchange period earlier this month, would be an integral part of Carlton in 2009 and beyond.
"To have someone with that presence out in the middle, especially at centre bounces, will be fantastic for us," Ratten said.
"Where we sat with hit-outs at centre bounces, we were ranked around 16th – hopefully we can get our hands on the ball a little bit more around the stoppages and make that one of our focuses to really improve.
"Hopefully we can get closer to one than 16 in that area.
"It's a huge boost [having him]. At 206cm, he's about the same size as Justin Madden was."
He said Warnock would be eased into pre-season training. "We'll just take it easy with Robbie in the first week," Ratten said.
Ratten also said the 16 players who started pre-season training on Monday, were in better nick than last year.
"This group has come back in really good shape and that gives us a chance to set a good foundation over the next few months," he said.
"It's all low-key this week, tomorrow they have a VO2 max [aerobic capacity] test, so we'll see how they're travelling from a fitness point of view. Each day will have something different from a testing point (of view).
"Last year I thought we might have come back a little bit not in the correct manner, you could say.
"So far, the boys who have come back have been in tip-top shape - some blokes have had time off and have improved their skinfolds, their weight and I suppose their physical appearance as well.
"Nearly every player has bettered his skinfold or the target set for him, so that's a really big plus for us."
